Air raid alarm



N 1953 w. o. SPOON ET AL 2,558,192

AIR RAID ALARM Filed April 18, 1951 2 Sheets-Sheet l //\/L-/E/\/ TUFFE JACK DREESEL JR. /5 i WALTER o. SPOON ,4 TTUF/VE/ Nov. 3, 1953 w. o. SPOON ET AL 2,658,192

AIR RAID ALARM Filed April 18, 1951 2 Sheets-Sheet 2 //\/z/E/\/TUE5 JACK DRESSEL JR. WALTER o. SPOON ,4 7- FU /Viv ate an all clear signal of steady pattern.

Patented Nov. 3, 1953 UNITED STATES PATENT OFFICE AIR RAID ALARM Walter 0. Spoon and Jack Dressel, J12, Goldendale, Wash.

Application April 18, 1951, Serial No. 221,691

2 Claims.

'This invention relates generally to audible or some alarms and more particularly to means for producing at will either a steady or pulsating noise of the siren type which will be both distinctive and penerating.

It is a principal object of this invention to provide an air raid alarm giving means having a distinctive signal and of which means any numberof duplicates can be made whereby, by

the widely distributed useof alarm giving means of this type, the distinctive signal will be generally recognized and instantly understood.

It is a second object of this invention to pro- "vide an air raidalarm means capable of making use, for its specific purpose, of the existing radios,

public addresssystems, and similar loud speaker 'systemswidely used and well known today.

Itis a third object'of this invention to provide 1a signal generating'means capable of generating a distinctively, varying electromotive force which ean "be impressed on an electromagnetic loud netic inserts through said gap and thereby vary the'flux density in the iron circuit of said electromagnet to 'vary the electromotive force generated in an insulated conducting wire coiled on said iron circuit.

It is a fifth object to provide means for varying to a desired pattern the speed of rotation of said'nonmagnetic disc.

It is a sixth object to drive said rotating discwith an electric'motor and to control the speed pattern of said disc by a switch in the energizing circuit of said motor.

It is a seventh object of this invention to provide a motor driven cam adapted to open and close the switch in the energizing'circuit of the disc rotating electric motor to control thespeed pattern of the disc.

It is an eighth object of this invention to provide a double throw switch'adapted on one throw to energize with said disc motor and said cam motor to generate-an air raid warning signal of adesired pulsating pattern and on the other throw to energize said disc motor only to gener- It is a ninth object of this invention to provide signal lights energized by the respective throws of said switch to indicate to the switch operator that the signal being generated is the signal intended to be generated.

How these and other objects are attained will be apparent from the following description referring to the attached drawings in which:

Fig. 1 is a view in perspective of the enclosing cabinet of the apparatus of this invention.

Fig. 2 is a perspective view with the rear enclosure removed of the interior of the cabinet shown in Fig. 1.

Fig. 3 is a plan viewlooking upward fromthe underside of the apparatusof Fig. 2.

Fig. 4 is a schematic representation and wiring diagram of the apparatus of Figs. 1, 2 and 3.

Referring now to the drawings, in Fig. 1 the cabinet front panel H on which the principal apparatus of this invention is carriedis shown mounted on the five sided rear enclosure [2 which forms the remainder of the cabinet for enclosing and protecting the apparatus.

Carried on insulating front panel H through clips i3 is insulating base l4 supporting on its underside by screws f5 and I6 disc operating electric motor l1 and cam operating electric motor [8 respectively. Secured by screws I!) to a hub, not shown, fixed to vertical shaft 20, indicated in Fig. 4, of motor I1 is nonmagnetic disc 2| through which have been inserted in a predetermined pattern magnetizable inserts 22. Also carried on base I4 through bracket, post 24 and spacer 25 is shielding conducting case 26 the open bottom of which faces the top of disc 2|. Fixed in case 25 in a V shaped permanent magnet (not shown), open downwardly so that its two poles are closely spaced, respectively, over the'two rows of insertsl22 of difierent radius from shaftzn. Wound on the permanent magnet .in case 26 isa pick-up coil (not shown) having terminals 21, 28 outside case 26.

Pressed on shaft29 of .cam motor I8 is cam 30. Adapted to ride over the undulating cam surface of cam 30 is roller 3| whoseaxle :32 is journalled as shown in the free end of resilient lever -33 having its other end secured to.the insulating enclosing case 34 of a normally open electric switch having an operating stem 3'5guided in case 34 and terminals '36 and 31 extending through case 34. Case 34 is secured to base M by screws 38 and so positioned that the switch in case 34 is open as roller-3| rides in a valley of cam 30 and closed asroller 3l rides over-a peak of cam'30.

loud speaker Secured to the back of panel H by screws 39 is frame 4|] of a double throw manually operated switch having an operating lever 4| journalled on pin 42 in frame 40. As shown in Fig. l, lever 4| extends through hole 43 in panel H for operation from the front side of panel As indicated schematically in Fig. 4, lever 4| is adapted on throw to one side to close switch blades 44 and 45 on blades 45 and 41, respectively, and on throw to the other side to close switch blades 48 and 49 on blades 50 and respectively.

Receptacle 52 having insulated center terminal 53 and side terminal 54 carries lamp 55 and is mounted as shown on the rear of panel II with lamp 55 adjacent a hole in panel II in which is mounted green lens 55. Receptacle 51 having insulated center terminal 58 and side terminal 59 carries lamp 5!! and is mounted as shown on the rear of panel with lamp 50 adjacent a hole in panel l in which is mounted red lens 5 Signal output cable receptacle "i2 is secured to panel H by nut 53 threaded on a reduced section of receptacle 5?. extending through a hole in panel Resistors 55 and 55 are secured to the underside of base Hi. The front of the panel H is suitably marked to show the proper direction of throw of switch lever 4|.

Electric power is supplied to this apparatus through a common type of plug cord 61 connected to terminals LI, L2, as shown.

Wire 58 connects Ll with side terminals 54 and 59 of lamp receptacles 52 and 51. Wire 59 connects Ll with switch blade 55, cam switch terminal 35, and one Wire 1| connects L2 motor |1, one terminal with one terminal of disc of cam motor, and one terminal of resistor 56. Resistors 54, 55, and 55 are connected in series as shown. Wire 12 connects the other cam switch terminal 31, with the other terminal of condenser 55 and switch blade 46. Wire 13 connects switch blade 48 with the other terminal of disc motor l1 and with switch blade 44. Wire 14 connects switch blades 45 and 49 with the other terminal of resistor 54 and the other terminal of cam motor l8. Wire 15 connects switch blade 41 with lamp terminal 58. Wire 15 connects switch blade 5| with lamp terminal 53. Single conductor shielded cable 11 connects insulated terminal 21 of the pick up ,in case with the insulated center terminal 18 of output receptacle 52. The other terminal of the pick up coil is grounded to case 26. The output cable 11 has its shield grounded at one end 'to case 25 and at the other end to the metal case of receptacle 62.

Shown diagrammatically only in Fig. 4 is a horn 19, its input coil 85 and a cord 8| used to connect the output receptacle center terminal 18 with the loud speaker system of whatever type is required for the particular warning system used.

With a properly energized loud speaker system plugged into the output receptacle of the apparatus described and the apparatus connected to a source of electric power with cord 51 and with the doubie throw switch lever 4| in the center or neutral position, it is seen from the drawings that no operating part of the apparatus will be energized. However, if it is desired to broadcast a raid alarm, lever 4| can be thrown in the direction of the arrow pointing to the word Raid on panel When lever 4| is thus thrown, switch blade 45 is forced to contact blade 41 and switch blade 44 is forced to contact blade terminal of condenser 15.

coil

4B. When switch blade 45 contacts blade 41, a circuit between terminals LI and L2 is set up from LI through wire 68, lamp 50 (behind red lens 6|), wire 15, switch blades 41, 45, wire 14, cam motor |8 and wire 1| to L2. The only purpose of the circuit from wire 14, through resistors 64, 55 and 66 to wire 1|, paralleling cam motor l8 with the three resistors in series to divide the line voltage L! to L2 between the lamp 50 and the cam motor l8 according to the voltage requirements of each of them. It is seen that when switch blade 45 and 41 contact lamp 54 will light up behind red lens 6| and the motor I8 will start up causing cam 30 to revolve at constant speed.

At the same time, switch blade 44 will be forced into contact with blade 46 and a second circuit is set up from L| through wire 59, cam switch terminals 35, 31, wire 12, switch blades 46, 44, wire 13, disc motor I1 and wire 1| to L2. Condenser 14 is connected across cam switch terminals 35, 31 to prevent undue deterioration of the cam switch contacts. It is seen that when switch blades 45, 44 are in contact disc motor U will be energized when the cam switch is closed and deenergized when the cam switch is open and since cam motor is is revolving at constant speed, roller 3| riding the undulating face of cam .35 will cause lever 33 and stem 35 to periodically energize and tie-energize disc motor 11 causing disc 2| to accelerate and decelerate periodically causing a periodical increase and decrease in the rate at which the magnetic inserts 22 change the flux through the iron circuit of the magnet in case 25 and, therefore, cause an electromotive force to be generated in the pick-up coil wound on the magnet in case 26 which will be periodically varying in both frequency and amplitude, thus causing the loud speaker system to emit a penetrating and distinctive sonic alarm signal.

When it is desired to stop broadcasting the alarm lever 4| is returned to its neutral position and the equipment is de-energized. Then, if it is desired to broadcast an all clear signal, lever 4| is thrown in the direction of the arrow on panel pointing to the word Clear on the panel. This throw of lever 4| causes switch blades 45 and 49 to contact with blades 51] and 5|, respectively. The closing of contact 49 on contact 5| sets up a circuit from Li through wire 68, lamp 55 (behind green lens 55), switch blades 5|, 49, wire 14, cam motor l8, and wire 1| to L2, thus showing a green light on the front of the panel and setting cam motor I8 into operation. At the same throw of lever 4| blade 48 will be put into contact with blade 5|) and a circult will be set up from Ll through wire 59, blades 59, 48, wire 13, disc motor l1 and wire 1| to L2 thus setting the disc motor into operation at con stant speed. While cam motor H3 is operating in this case, it does not affect the operation of the d sc motor since switch blades 50, 48 energize d sc motor directly from LI and L2. The Clear signal will, therefore, not be generally undulatmg 1n frequency and amplitude as the Raid signal waihseen to be, but will be generally cons an in e at cm i into disc 2! p of nsertion of inserts 22 Having thus described a preferred form of the device of this invention and explained its u We claim:

1. An air raid signal producin mech adapted to be controlled by a double throw to g1ve an audible steady alarm responsive to one throw of said double throw switch and an interrupted audible alarm responsive to the other throw of said double throw switch, said mechanism comprising in combination a source of electric power, a disk of non-magnetic material, a first electric motor adapted to rotate said disk, a plurality of magnetic inserts in said disk, means forming a magnetic circuit, said magnetic circuit being adapted to include said insert once at each revolution of said disk, an electromagnetic loud speaker, electric circuit means adapted to couple said magnetic circuit with said loud speaker, means for energizing said magnetic circuit and said loud speaker, an electric switch, a rotatable cam, a second electric motor adapted to rotate said cam, said cam being adapted to close and open said switch as said cam is rotated, a double throw switch, and circuit means adapting said double throw switch in one of its throw positions to energize said first motor from said source of power, and in the other of its throw positions to energize said first motor from said source of power through said electric switch and to energize said second motor from said power source.

2. In combination a source of electric power, a disk of non-magnetic material, a first electric motor adapted to rotate said non-magnetic disk, a plurality of magnetic inserts in said disk, said inserts being set into said disk in a desired pattern, means forming a magnetic circuit, said magnetic circuit means being adapted to overlay said disk whereby the reluctance of said magnetic circuit will vary as said disk is rotated and said magnetic inserts enter and leave said magnetic circuit in a desired pattern, an electromagnetic loud speaker, circuit means adapted to couple said loud speaker to said magnetic circuit, an electric switch, a rotatable cam, a second electric motor adapted to rotate said cam, said cam being adapted to close and open said switch as said cam is rotated by said second motor, a double throw switch, and circuit means adapting said switch in one of its throw positions to energize said first motor from said source of power and in the other of its throw positions to energize said first motor through said electric switch from said source of power and to energize said second motor from said source of power.

WALTER O. SPOON. JACK DRESSEL, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,221,814 Reid Nov. 19, 1940 2,381,224 Mitchell et al Aug. 7, 1945 2,500,063 Crane Mar. 7 1950 

